Snapshot A 19-year-old female presents to the gynecologist for the first time. She reports that she has not started to menstruate. The OB/GYN notes that the patient is short-statured and has notably delayed breast development with webbing skin between the neck and shoulders. Introduction Genetic disorder caused by a missing X chromosome in females (45XO) Most common cause of primary amenorrhea (uterus present) Most patients are infertile Associated with greater risk for developing co-morbities including cardiac problems hypertension coarctation of the aorta aortic valve abnormalities (e.g. bicuspid aortic valve) renal dysfuncton horseshoe kidney diabetes cystic hygroma cataracts osteoporosis thyroid problems Presentation Symptoms amenorrhea short stature webbed neck Physical exam amenorrhea with present uterus coarctation of the aorta may be evident on auscultation low hairline in back low-set ears extremity edema hypertension signs of thyroid dysfunction stool guaiac may identify GI bleeding Evaluation Diagnosis is based primarily on physical exam and patient history Buccal smear for absent Barr bodies is outdated diagnostic method Labs low anti-Mullerian hormone Karyotype analysis diagnostic test of choice may identify 45XO, confirming diagnosis Fertility testing may identify 45XO, confirming diagnosis Endoscopy may identify GI telangiectasias causing lower GI bleeding Differential Down syndrome, polycystic ovarian disorder Treatment Medical management Growth hormone may help patient achieve normal height Estrogen/progesterone hormone replacement allows development of secondary sex characteristics may aid fertility IVF may assist in reproduction Prognosis, Prevention, and Complications Prognosis good to very good with appropriate treatment most patients live complete lives Prevention no preventive measures are available for this condition Complications coarctation of the aorta, ovarian dysgenesis, GI telangiectasias